For the AW'21 collection PUMA presents its flagship trailrunner Voyage NITRO. This outdoor shoe boasts a number of features, such as a two-part NITRO sole and a GORE-TEX membrane. Learn about the technology and unique features of a modern trail running shoe, most bonkers runs around the world and how the Voyage NITRO's features relate to all of it in our article.

Produced by TECHUNTER Media.

Layout: Alexander Zabelin [THM].
Words: Nikita Osaulenko [THM].
Ph: Ivan Dzhatiev [THM].
Ph asst: Vasilisa Mityaeva.

"Trails" in "trail running", it must be said, are very nominal. Throughout the history of the sport, man has repeatedly challenged himself to find these "trails" and conquer them on his own: just look at the numerous marathons and ultramarathons taking place in various remote parts of the world.

There are no limits to trail running, be it a high mountain or a deep forest, hot or icy desert. Even a special kind of trail - skyrunning, or running in the mountains - has emerged. Nominally skyranning is organised by the International Mountaineering Federation, but its origins lie in trail running. Over the past 20 years the number of trail runners has grown to several millions, while some courses have achieved iconic status.

One such test of strength is the Ultra Trail du Mont Blanc marathon, held in the French Alps near the town of Chamonix. Mont Blanc is traditionally associated with stunning views. However, the athletes on this course don't have a lot of spare time to admire them: the marathoners have to overcome 170 kilometres with a combined altitude gain of 10,000 metres over passes, forests, rocky trails in the face of changing day and night as well as the vagaries of the weather.

UTMB is considered to be one of the most difficult and at the same time prestigious ultramarathons for a reason: the complexity of the route makes it a real challenge for even the most experienced of runners. The main adversary for the participants is the terrain, replete with rocky trails. The right footwear is absolutely crucial to provide protection and support for the foot.

Our hero today, The Voyage NITRO, has a toe design that prevents the ingress of foreign bodies (such as stones) which interfere with comfort and can lead to injury. The sock is made of a soft stretch material that securely and pleasantly fixes around the ankle.

Also worth highlighting is the overall design of the silhouette: the "box" in the heel is slightly narrower and has a strong "cup" that securely fixes the foot. This design provides support and protects the foot from excessive rotation on unstable surfaces.

Another important stabilizing element is the lacing. Not only is it based on anatomic OPTIFIT technology, but also has the advantage of flat laces which will not come undone at the most inopportune moment and over tighten the foot.

The upper's construction includes several polyurethane cushioning elements in the form of an overlap on the sides of the trainer. This is particularly noticeable in the toe section where the thickest such insert is placed, designed to protect the toes from stones. Another plus side of the upper's construction is a slightly raised toe and instep - this adds space inside the front 'box' and also levels out the possibility of chafing, if the fit is too tight on the forefoot.

Another no less famous trail is the Gobi March - here marathon runners have a seven-day run of 250 kilometres through Mongolia's endless steppes, sand dunes and majestic rocky valleys.

The route passes alongside the Khar Bukh Balgas fortress, numerous temples, traditional Mongolian ger villages, the UNESCO World Heritage Centre in the Orkhon valley and finally ends in the ancient city of Karakorum.

In addition to sturdy protection materials, a trail shoe also needs grip and cushioning technology. The midsoles, or midsole, must be both resilient and versatile enough to provide comfortable cushioning on challenging routes with steep descents and hard rock slab landings.

The midsole technology in the Voyage NITRO features two materials. While the trail shoe is dominated by the trend for an impressive single-component EVA midsole, PUMA sticks with the time-tested principle of combining foam with different densities in the more familiar sizes. Responsible for cushioning here are PROFOAM LITE, which fills most of the midsole, and NITRO FOAM at its base. This combination results in both explosive energy transfer during active exertion and a comfortable sensation during a measured cross-country.

The NITRO FOAM is a rather interesting technology used as stabilizing inserts in the forefoot and heel. It is an EVA with the addition of nitrogen, in simple terms. This formula allows for a lightweight and at the same time elastic foam.

Interesting fact: PUMA was the first sports shoe manufacturer in the 1960s to use vulcanisation and compression molding to bind the sole to the upper's structure. What it does is melt the sole material at 200 degrees, place it in a mould and then apply external pressure to fix the uppers. Prior to the discovery of this technology, shoes were usually fastened by mechanical means: nails, threads and screws. Vulcanisation made it possible to reduce the weight of the product and increase its reliability.

The Voyage NITRO Outsole is made from a tough and tenacious PUMAGRIP material to ensure a secure grip. This is achieved not only by the physical properties of the rubber used for the sole, but thanks to a sufficiently wide tread with high spikes, equally suitable for unpaved, sandy, or stony trails.

Stones and sand are not, however, the only possible obstacles marathon runners face. The Jungle Ultra in South America, for example, has a very creative approach to trail running. This ultramarathon takes place in the Amazon rainforest that lies within the Manu National Park in Peru.

The trail is characterised by high temperatures and extreme humidity that creates a greenhouse effect. Moreover, the marathon runners have to cross more than 70 (!) tropical rivers and streams along the route.

The problem of getting clothes wet, and subsequently losing comfort, haunted mankind until the second half of the 20th century. In 1969, American manufacturer W. L. Gore and Associates came up with the solution in the form of a PTFE membrane, or Teflon, which was a porous film that allowed the vapour from the skin to escape and prevented it from getting wet. The pores in the membrane were the right size: not too large to keep water molecules out, and not too small to wick away vapour molecules.

This solution is also used in the Voyage NITRO. The GORE-TEX membrane is implemented as a sock sewn inside the trainer. Such a construction keeps the entire foot dry and evenly disperses moisture away from the entire surface of the foot. Thanks to GORE-TEX, marathon runners can tackle long distances over kilometres involving wet and rainy regions, such as Peru's The Jungle Ultra.

Behind the rich technological content hides another feature: weight. It's 254 grams for the women's 4.5UK and 304 grams for the men's 8UK. These are great results for trail running shoes in principle, especially considering the presence of the GORE-TEX membrane, which structurally adds weight. In this class, better results can only be achieved with more expensive materials and design constraints, which in turn will affect the final price and comfort level.

Light weight of the shoe is one of the biggest possible advantages in trail running. Light enough trainers don't strain your legs in already extreme situations.

Challenging ultra-marathon distances are even more challenging on loose terrain or - even more challenging - sand. Firstly, a high toe prevents sand from penetrating the shoe, thereby causing discomfort and weighing the shoe down. Secondly, the light weight coupled with the wide tread allows for better traction on sandy terrain.

The Marathon des Sables is a 250-kilometre race, which athletes must run in six days, mostly on the sands of the vast Sahara Desert. You have to run in constant expectation of sandstorms and sudden changes in weather - 30-degree heat during the day turns to 12 degrees at night. Mauro Prosperi, the Italian pentathlete, who lost his way in 1994 to a sandstorm for 11 days, says this about the conditions of the race: